Plain concrete may have compressive strength, i.e., its ability to resist crushing loads; however, its tensile strength may be only about 10% of its compressive strength. Its tensile strength may be so low that it may be nearly disregarded in design of most concrete structures. Reinforced concrete may be a combination of adequate reinforcement (such as steel bars with raised lugs called deformations) and concrete designed to work together to resist applied loads. Properly placed reinforcement in concrete may improve its compressive and tensile strength.